Arg-735 of the 100-kDa subunit a of the yeast V-ATPase is essential for proton translocation

@article{KawasakiNishi2001Arg735OT,
  title={Arg-735 of the 100-kDa subunit a of the yeast V-ATPase is essential for proton translocation},
  author={Shoko Kawasaki-Nishi and Tsuyoshi Nishi and Michael Forgac},
  journal={Proceedings of the National Academy of Sciences of the United States of America},
  year={2001},
  volume={98},
  pages={12397 - 12402}
}
The vacuolar (H+)-ATPases (V-ATPases) are ATP-dependent proton pumps that acidify intracellular compartments and pump protons across specialized plasma membranes. Proton translocation occurs through the integral V0 domain, which contains five different subunits (a, d, c, c′, and c"). Proton transport is critically dependent on buried acidic residues present in three different proteolipid subunits (c, c′, and c"). Mutations in the 100-kDa subunit a have also influenced activity, but none of… 

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Function and Subunit Interactions of the N-terminal Domain of Subunit a (Vph1p) of the Yeast V-ATPase*
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Results suggest that a localized region of the N-terminal domain is important in anchoring the peripheral stator in V1V0, suggesting that in vivo dissociation of the V-ATPase generates a V0 domain that does not passively conduct protons.
Definition of Membrane Topology and Identification of Residues Important for Transport in Subunit a of the Vacuolar ATPase*
TLDR
A tentative model for the proton-conducting hemichannels in V0 is proposed in which the cytoplasmic hemichannel is located at the interface of TM7 and TM8 of subunit a and the proteolipid ring, whereas the lumenal hemich channel is located within sub unit a at the interfaces of TM3, TM4, and TM7.
Characterisation of the human H⁺-ATPase a4 subunit.
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Findings indicate a direct link between V-ATPase and glycolysis, via the C-terminus of the pump's a subunit, and suggest a novel regulatory mechanismBetween V- ATPase function and energy supply.
Mutational Analysis of the Non-homologous Region of Subunit A of the Yeast V-ATPase*
TLDR
Results suggest that changes in the non-homologous region can also alter in vivodissociation of the V-ATPase independent of effects on activity.
Structural Analysis of the N-terminal Domain of Subunit a of the Yeast Vacuolar ATPase (V-ATPase) Using Accessibility of Single Cysteine Substitutions to Chemical Modification*
TLDR
The results provide an experimental test of the proposed model and have identified regions of the N-terminal domain of subunit a that likely serve as interfacial contact sites with the peripheral V1 domain that may participate in interactions that regulate V-ATPase assembly.
Arginine Residue at Position 573 in Enterococcus hirae Vacuolar-type ATPase NtpI Subunit Plays a Crucial Role in Na+ Translocation*
TLDR
Results indicate that NtpI Arg-573 is indispensable for sodium translocation and for the cooperative features of E. hirae vacuolar-type ATPase.
TM2 but Not TM4 of Subunit c″ Interacts with TM7 of Subunit a of the Yeast V-ATPase as Defined by Disulfide-mediated Cross-linking*
TLDR
Interaction of subunits a and c″ using disulfide-mediated cross-linking is analyzed, indicating that the helical face of TM7 of subunit a containing Arg735 interacts with the helicals of TM2 of sub unit c″ centered on Ile105, with the essential glutamic acid residue located near the opposite border of this face compared with TM4 of sub Unit c′.
Analysis of the Membrane Topology of Transmembrane Segments in the C-terminal Hydrophobic Domain of the Yeast Vacuolar ATPase Subunit a (Vph1p) by Chemical Modification*
TLDR
The results support an eight transmembrane helix (TM) model of subunit a in which the C terminus is located on the cytoplasmic side of the membrane and provide information on the location of hydrophilic loops separating TM6, 7, and 8.
Subcellular distribution of the V-ATPase complex in plant cells, and in vivo localisation of the 100 kDa subunit VHA-a within the complex
TLDR
All three sets of results show that V-ATPase contains VHA-a protein that interacts in a specific manner with other subunits, in agreement with the hypothesis that the different isoforms of VHA -a may localize on distinct endomembrane compartments as it was shown for its yeast counterpart Vph1.
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